Stent thrombosis after switch from nongeneric to generic clopidogrel

The U.S. Food and Drug Administration recently approved generic versions of clopidogrel bisulfate which should lower the cost and improve compliance in patients requiring dual antiplatelet therapy post stent placement. However, there is marked inter-individual variability in the metabolism and intestinal absorption of clopidogrel. The different binders and fillers used in the generic versions can possibly affect absorption and reduce the bioavailability of the drug. We report a case of very late stent thrombosis in a patient eight days after the switch to generic clopidogrel bisulfate from branded clopidogrel (Plavix). The patient had received a sirolimus drug eluting stent almost three years prior to presentation and was on chronic dual antiplatelet therapy. Subsequent to the event, she was found to be a poor metabolizer of clopidogrel. Although in most cases the use of generic clopidogrel is efficacious and safe, certain individuals, such as poor metabolizers, might be susceptible to increased clinical events when switching. We suggest any suspected cases should be reported to Medwatch so the clinical relevance could be determined.